In the carpet-tufting field, there is considerable emphasis placed on developing new, eye-catching carpet patterns to keep up with changing consumer tastes and increased competition in the marketplace. With the introduction of computer controls for tufting machines, as disclosed in U.S. Pat. No. 4,867,080, greater precision and variety in designing and producing tufted patterned carpets has been possible while also enabling enhanced production speeds. In addition, computerized design centers have been developed, such as shown in U.S. Pat. No. 5,058,518, to enable designers to design and develop visual representations of patterns on a computer and generate the pattern requirements such a yarn feed, pile heights, etc. that will be input into a tufting machine controller for forming such patterns.
Traditionally, pattern attachments such as roll or scroll pattern attachments have been used for controlling the feeding of selected groups of yarns to the needles of a tufting machine having such a pattern attachment. Such roll and/or scroll pattern attachments include a series of yarn feed rolls that feed the selected groups of yarns to selected ones of the needles. By controlling the operation of these feed rolls, the rate of feed of the yarns to the needles is controlled for varying the pile heights of the tufts of yarn formed in a backing material passing through the tufting machine, so as to enable some tufts of yarn to be back-robbed and hidden by adjacent tufts in order to form different pattern repeats across the width of the backing material.
A significant problem, however, that exists with the use of such traditional pattern attachments and even with more recently developed scroll type pattern attachments such as disclosed in U.S. Pat. No. 6,244,203, which discloses a servo-motor controlled scroll type pattern attachment for a tufting machine, has been the requirement for tube banks that extend from the pattern attachment feed rolls at varying lengths across the tufting machine for feeding the yarns from the pattern attachment feed rolls to the needles. Such tube banks include a plurality of tubes of varying lengths, along which the yarns are urged or fed to their respective needles. The problem with such tube banks generally has been that the yarns passing through the longer tubes are typically subjected to increased drag or friction as they are passed along the increased length of their tubes, such that it has been difficult to achieve high amounts of precision and responsiveness to changes in the pattern across the width of the carpet. The use of the tube banks further adds a significant cost both in terms of manufacture and set up of the machines, as well as significantly increasing the complexity of operation of the tufting machines.
In addition, systems such as disclosed in U.S. Pat. Nos. 6,244,203 and 6,213,036 have attempted to achieve greater precision and control of the feeding of the yarns by the pattern attachment through the use of an increased number of feed rolls and drive motors for feeding selected ones of the yarns to selected needles. However, as the number of yarn feed rolls and number of motors associated therewith for driving such individual yarn feed rolls is increased, there is likewise a corresponding increase in the costs of such pattern attachments. In addition, increasing the number of motors and feed rolls further increases the complexity of manufacturing such pattern attachments, as well as the set up of such attachments as a part of a tufting machine when the machine is installed in the field. In addition, the reliability of such systems generally becomes of greater concern, given the increased number of feed devices being controlled by the tufting machine controller and the corresponding amount of wiring and electrical connections that must be assembled and made in the field with the set up of the tufting machine and pattern attachments.
Accordingly, it can be seen that a need exists for a system that addresses these and other related and unrelated problems in the art.